Volunteers collect plastic waste that has accumulated on the edge of the seashore called Lake Siombak waters during the commemoration of World Environment Day in Medan, North Sumatra on June 4, 2025.

World Environment Day in 2025 which focuses on efforts to end plastic pollution, where World Environment Day joins the UNEP-led Beat Plastic Pollution this year to end plastic pollution including in the marine environment. Plastic pollution exacerbates the deadly impacts of three planetary crises as the climate change crisis, the nature crisis, the loss of land and biodiversity, and the pollution and waste crisis. According to environmental activist, Yudha Pohan said. "Yes, this year we are doing a clean-up action at Lake Siombak, as the Lake Siombak is one of the priorities of the City of Medan, and this is a reliable location to see the sunset. This action is as a lake that occurs ebb and flow from sea water, when the tide is high, and the garbage also enters the edge of Lake Siombak".